1. Background of the Invention
The present invention relates to a combination telescope and range finding apparatus, including
a telescoping sight provided with a telescope housing one end of which receives an objective lens and the other end of which receives an eyepiece and which defines a beam path therebetween,
an opto-electronic range finder provided with emitter-receiver optics for optical measuring beams and evaluation electronics for timing the interval between emission and reception of a measuring beam and for determining the distance on the basis thereof, and
a beam splitter within the beam path of the telescope housing for coupling and decoupling measuring beams into the part of the beam path directed toward the objective lens.
Such an apparatus is known, for instance, from European Patent EP 0,709,705. The publication discloses a telescoping sight for fire arms and is provided with a laser range finder integrated into the telescope housing. Emitted and received measuring beams are coupled and decoupled into the beam path toward the objective lens by separate beam splitters. The beam splitters are fixedly supported by the telescope housing, and for adjusting the sighting of the telescope the objective lens is mounted adjustably relative to the housing of the telescoping sight.
On the one hand, such a structure is complex as it requires two separate beam splitters and an adjustable objective lens; on the other hand, it is not possible simply to convert extant telescoping sights, for conventional telescoping sights utilize a movably mounted internal tube containing a target mark and reversal optics; no objective lens is provided which is mounted for special movements.
2. The Prior Art
It is, therefore, an object of the invention to provide a combination telescope and range finder apparatus which may be constructed in a particularly simple manner by conversion of existing telescopes. In an apparatus of the kind referred to supra, the object is accomplished by the an opening provided in a side wall of the telescope housing and the range finder being contained in a separate measuring housing adapted for mounting on said side wall, the emitter-receiver optics being directed toward the said opening.
In this manner, conversion of conventional telescoping sights available in the market is made simple.
In accordance with a preferred embodiment of the invention, the opening is hermetically sealed by a cover which is transparent to measuring beams. In this manner, the telescope is protected from moisture entering and from the possibility of fogging. The telescope remains sealed even in case of a repair.
The invention is particularly suitable for use with such commercially available telescopes in which the telescope housing is provided with an adjustably mounted internal tube of the kind which is traversed by the beam path, renders a target mark and optionally contains reversal optics. In such cases, the invention provides for the beam splitter to be mounted on the internal tube. More particularly, the target mark may be provided, preferably as a hairline graticule, on the side of the beam splitter facing the objective lens. This would require minimum adjustment of a telescoping sight.
In order in such cases to prevent shifting of the focus of the measuring beam coupled into the beam path relative to the target mark as a result of the internal tube being tilted relative to the telescope housing during sighting adjustments, a portion of the section of measuring beams between beam splitter and emitter-receiver optics in accordance with a preferred embodiment of the invention is a focal. This allows for movement of the internal tube relative to the telescope housing without the focus of the measuring beam being shifted in any significant way.
In accordance with the invention, this may be accomplished in a structurally simple and compact manner by each of the telescope housing and the internal tube or the beam splitter supporting a lens or group of lenses which between them form the mentioned focal portion.
In any case, emitter-receiver optics with spatially separated emitting and receiving components provided at their input with a beam splitter for correspondingly splitting of emitted and received measuring beams, is deemed to be particularly advantageous. In this fashion, cross talk from the emitter to the receiver component may be substantially reduced.
In this connection, it is particularly advantageous to structure the beam splitter as two opposing 90xc2x0 deflector prisms with the mentioned opening aligned centrally thereof. This results in a measuring housing of particularly low structure.
Alternatively, the beam splitter may be a physical beam power splitter, e.g. a 50%/50% splifter, a polarizing splitter, etc., so that both emitted and received measuring beams may each utilize the entire surface of the objective lens.
In accordance with the invention, an especially compact structure of the measuring housing is obtained by arranging the emitter and receiver components axially spaced from each other on a circuit board extending parallel to the axis of the telescope housing.